/* Copyright (c) 2008, RDFfs - Andrea Marchesini <baku@morlardf.net>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the <organization> nor the
 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */
#ifdef HAVE_CONFIG_H
#include <config.h>
#else
# error Use configure; make; make install
#endif

#include <rdffs.h>

/* These 4 functions implement the reader/writer algorithm */

void
rdffs_lock_writer (void)
{
  g_mutex_lock (rdffs_input.mutex_writer);
}

void
rdffs_unlock_writer (void)
{
  g_mutex_unlock (rdffs_input.mutex_writer);
}

void
rdffs_lock_reader (void)
{
  g_mutex_lock (rdffs_input.mutex_reader);

  rdffs_input.readers++;

  if (rdffs_input.readers == 1)
    g_mutex_lock (rdffs_input.mutex_writer);

  g_mutex_unlock (rdffs_input.mutex_reader);
}

void
rdffs_unlock_reader (void)
{
  g_mutex_lock (rdffs_input.mutex_reader);

  rdffs_input.readers--;

  if (rdffs_input.readers == 0)
    g_mutex_unlock (rdffs_input.mutex_writer);

  g_mutex_unlock (rdffs_input.mutex_reader);
}

/* EOF */
